Universidade Federal de Viçosa (UFV), Laboratório de Enzimologia e Bioquímica de Proteínas e Peptídeos, Departamento de Bioquímica e Biologia Molecular, BIOAGRO/INCT-IPP, Av. Peter Henry Rolfs, s/n, Campus Universitário, 36570-900 Viçosa, MG, Brazil.
Universidade Federal de Viçosa (UFV), Departamento de Entomologia/BIOAGRO, Av. Peter Henry Rolfs, s/n, Campus Universitário, 36570-900 Viçosa, MG, Brazil.
An Acad Bras Cienc. 2021 Aug 9;93(3):e20191456. doi: 10.1590/0001-3765202120191456. eCollection 2021.
The spittlebugs Mahanarva spectabilis economically challenges cattle production of neotropical regions, due to its voracious feeding on tropical grasses. Here, we evaluated biochemical responses of the interaction between M. spectabilis and the widely cultivated tropical grasses Brachiaria spp. (i.e., brizantha and decumbens) and elephant grasses (cvs. Roxo de Botucatu and Pioneiro), regarding lipoxygenases, protease inhibitors, phytohormones, and proteolytic activities in the midgut of M. spectabilis. The M. spectabilis-infested grasses increased lipoxygenases activity, except for cv. Pioneiro. The levels of the phytohormones jasmonic and abscisic acids were similarly low in all genotypes and increased under herbivory. Furthermore, salicylic acid concentration was constitutively higher in Brachiaria sp., increasing only in spittlebug-infested B. decumbens. M. spectabilis infestations did not induce increases of protease inhibitors in any forage grass type. The trypsin activity remained unaltered, and the total proteolytic activity increased only in B. decumbens-fed insects. Our findings revealed that most forage grasses exposed to spittlebugs activate the lipoxygenases pathway, resulting in increased abscisic and jasmonic acids. However, greater amounts of these hormones do not induce protease inhibitory activity in response to spittlebug attack. This knowledge certainly helps to guide future projects aiming at reducing the impact of spittlebugs on forage production.
沫蝉会大量取食热带牧草，从而对新热带地区的畜牧业生产造成严重的经济损失。在这里，我们评估了沫蝉与广泛种植的热带牧草（如 brizantha 和 decumbens）和象草（cv. Roxo de Botucatu 和 Pioneiro）之间相互作用的生化反应，包括沫蝉中肠的脂氧合酶、蛋白酶抑制剂、植物激素和蛋白水解活性。受沫蝉侵害的牧草会增加脂氧合酶的活性，但 cv. Pioneiro 除外。所有基因型的茉莉酸和脱落酸水平都很低，但在受到取食后会增加。此外，在 Brachiaria sp. 中水杨酸浓度一直较高，只有在受沫蝉侵害的 B. decumbens 中才会增加。在任何一种牧草类型中，沫蝉的侵害都不会诱导蛋白酶抑制剂的增加。胰蛋白酶活性保持不变，只有在喂食 B. decumbens 的昆虫中总蛋白水解活性才会增加。我们的研究结果表明，大多数暴露于沫蝉的牧草会激活脂氧合酶途径，导致脱落酸和茉莉酸含量增加。然而，这些激素的大量增加并不会诱导蛋白酶抑制活性来应对沫蝉的攻击。这些知识无疑有助于指导未来的项目，以减少沫蝉对牧草生产的影响。
